U.S. patent number 5,304,346 [Application Number 07/965,514] was granted by the patent office on 1994-04-19 for welding material for low coefficient of thermal expansion alloys.
This patent grant is currently assigned to INCO Alloys International, Inc.. Invention is credited to Robert A. Bishel, David B. O'Donnell.
United States Patent |
5,304,346 |
O'Donnell , et al. |
April 19, 1994 |
Welding material for low coefficient of thermal expansion
alloys
Abstract
The invention provides a welding material for welding iron
containing low CTE alloys. The filler metal contains 25-55% nickel,
0-30% cobalt, 0.05-0.5% carbon, 0.25-5% niobium and balance iron
with incidental impurities. The welding material also is operable
with fluxes for submerged arc welding. In addition, the welding
material may be configured to function as a flux coated or
flux-cored electrode.
Inventors: |
O'Donnell; David B.
(Huntington, WV), Bishel; Robert A. (Huntington, WV) |
Assignee: |
INCO Alloys International, Inc.
(Huntington, WV)
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Family
ID: |
27416906 |
Appl.
No.: |
07/965,514 |
Filed: |
October 23, 1992 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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773234 |
Oct 9, 1991 |
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645822 |
Jan 25, 1991 |
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604578 |
Oct 26, 1990 |
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Current U.S.
Class: |
420/580; 148/23;
148/24; 148/26; 148/310; 148/312; 148/336; 148/426; 420/459;
420/581; 420/94; 420/95 |
Current CPC
Class: |
B23K
35/3605 (20130101); B23K 35/3066 (20130101) |
Current International
Class: |
B23K
35/30 (20060101); B23K 35/36 (20060101); C22C
038/08 () |
Field of
Search: |
;420/580,581,582,583,584,585,586,94,95,459
;148/23,24,26,310,312,336,426 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1957944 |
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May 1971 |
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DE |
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2095416 |
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Feb 1972 |
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FR |
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Primary Examiner: Bean; W.
Assistant Examiner: Ip; Sikyin
Attorney, Agent or Firm: Biederman; Blake T. Steen; Edward
A.
Parent Case Text
This is a continuation application of Ser. No. 07/773,234, filed
Oct. 9, 1991 abandoned which was is a continuation-in-part of
copending application Ser. No. 07/645,822 filed on Jan. 25, 1991,
now abandoned. Application Ser. No. 07/645,822 is a
continuation-in-part of copending application Ser. No. 07/604,578
filed Oct. 26, 1990, now abandoned.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A welding material useful for welding iron containing low
coefficient of thermal expansion alloys consisting essentially of
by weight percent about 25-55% nickel, about 0-30% cobalt, at least
0.12% carbon to a maximum of 0.5% carbon, about 0.25-5% of niobium
and tantalum, about 0-0.5% element selected from the group
consisting of magnesium, zirconium and cerium, less than about 0.1%
sulfur, less than about 1% silicon, less than about 0.1%
phosphorous and balance iron with incidental impurities.
2. The welding material of claim 1 wherein said alloy contains
0.5-3% niobium.
3. The welding material of claim 1 including about 0-3% manganese,
about 0-5% copper, about 0-3% titanium and about 0-1% aluminum.
4. The welding material of claim 1 including about 0.5-3% of
niobium and tantalum, about 0-1.5% manganese, about 0-2% copper,
about 0-1.5% titanium, about 0-0.5% aluminum, about 0-0.1%
magnesium, about 0-0.1% cerium, about 0-0.1% zirconium, less than
about 0.05% sulfur, less than about 0.5% silicon and less than
0.05% phosphorous.
5. The welding material of claim 1 wherein said welding material
contains magnesium and weight percent of said magnesium is greater
than weight percent sulfur contained in said welding material.
6. The welding material of claim 1 wherein said welding material
contains about 0 to 0.1% magnesium.
7. The welding material of claim 1 wherein said welding material is
coated with a flux.
8. The welding material of claim 7 wherein said flux consists
essentially of about 10-40% alkaline metal carbonate, about 0-45%
cryolite, about 0-40% alkaline metal fluoride, about 0-45% rutile,
a binder and about 5-45% cryolite plus alkaline metal fluoride.
9. The welding material of claim 7 wherein said flux consists
essentially of, by weight percent, about 20-35% alkaline metal
carbonate, about 0-35% cryolite, about 0-30% alkaline metal
fluoride, about 10-35% total cryolite plus alkaline metal fluoride,
about 20-45% rutile, about 0-20% zirconia, about 0-10% magnetite,
about 0-15% of 80% MnO-5% SiO.sub.2 -10% Fe weld agent, about 0-15%
FeNb, about 0-15% Fe-C, about 0-15% NiNb, about 0-15% Ni-C, about
0-15% FeTi, about 2-5% bentonite, about 0-2% hydroxyethylcellulose
and 0-4% binder.
10. A welding deposit useful for combining iron-containing low
expansion alloys, said welding deposit as measured without dilution
from a base metal consisting essentially of by weight percent about
31 to 45% nickel, at least above 0.1% carbon to a maximum of 0.35%
carbon, about 0-2.5% manganese, about 0-0.1% magnesium, about
0.1-4% niobium plus tantalum, about 0 to 0.75% titanium, about 0 to
1% silicon, about 0 to 2% chromium, about 0 to 0.5% aluminum, about
0-4% copper, about 0 to 0.05% sulfur, about 0 to 0.05% phosphorous
and less than about 0.01% ingredient selected from the group
consisting of silver, boron, tin and zinc balance essentially iron
for proving a low coefficient of thermal expansion weld despot.
11. The welding deposit of claim 10 wherein said deposit contains
at least 0.12% carbon.
12. The welding deposit of claim 10 wherein said welding deposit
includes about 0 to 1.5% manganese, about 0 to 0.02% sulfur, about
0.5 to 3% niobium plus tantalum, about 0 to 4% copper and about 0
to 0.5% titanium.
13. The weld deposit of claim 10 wherein said welding deposit
includes a maximum of 0.25% carbon, 0 to 0.8% manganese, 0 to 0.01%
sulfur, 0 to 0.75% silicon, 1 to 2.5% niobium plus tantalum,
0.0005-0.075% magnesium and 0 to 0.4% titanium.
Description
TECHNICAL FIELD
This invention relates to welding of low coefficient of thermal
expansion alloys. In particular, this invention relates to welding
material for welding iron-containing low expansion alloys with or
without flux.
BACKGROUND OF THE INVENTION
Historically a combination of iron and nickel or cobalt has been
used to produce low coefficient of thermal expansion (CTE) alloys.
Invar 36 (36 Ni, balance Fe), Invar 42 (42 Ni, balance Fe) and
Kovar (29 Ni, 17 Co, 0.2 Mn balance Fe) are common low coefficient
of thermal expansion alloys. Welding of iron containing low CTE
alloys requires a weld with adequate ductility and strength. In
addition, for fabrication of welded low CTE alloys it is desired to
use a filler metal with a CTE closely matched to the base metal to
limit thermal deflections and strain.
Without further modification, low CTE base metals may be easily
drawn into filler metal wire. However, base metal filler metal is
highly subject to cracking resulting from impurities and a
relatively large solidification range of about 80.degree. Celsius.
Witherell, in U.S. Pat. No. 3,184,577 ('577), disclosed a filler
metal specifically designed for welding Invar. A combination of
titanium, carbon and manganese was used in the '577 patent to
control cracking during welding operations. Commercially, filler
metal of the '577 patent has been used for welding Invar 36 with
undesirable limitations. Filler metal disclosed in the '577 patent
cracks extensively when welding relatively thick sections of Invar.
In addition, filler metal of the '577 patent has been limited to
relatively slow gas tungsten arc welding (GTAW), because cracking
is excessive when welding with gas metal arc welding (GMAW). GMAW
is significantly quicker than GTAW and is generally preferred for
high volume fabrication. Furthermore, multiple pass welding with
Witherell's filler metal has caused excessive crack growth
problems.
In addition, submerged arc welding (SAW) may be used to further
increase welding rates. Submerged arc welding operability of a
filler metal is another highly advantageous property. Furthermore,
flux coated electrodes are useful for out of position welding where
it is difficult to weld by GTAW, GMAW or SAW.
It is an object of this invention to produce a welding material
having a coefficient of thermal expansion that matches the base
metal with sufficient strength and ductility.
It is a further object of this invention to produce a filler metal
capable of welding relatively thick sections of Invar without
cracking.
It is a further object of this invention to provide a filler metal
that may be gas metal arc welded without cracking.
It is a further object to produce a welding material that may be
used in multiple pass type welding operations without cracking.
It is a further object of the invention to produce a weld wire that
may be submerged arc welded.
SUMMARY OF THE INVENTION
The welding material of the invention may be used for GMAW
relatively thick sections of low CTE alloys. In fact, multiple pass
GMAW may be used without cracking. Furthermore, the welding
material of the invention facilitates rapid submerged arc welding
and may be flux coated for facilitating out of position welding.
The broad range of the invention preferably includes about 10-80%
nickel, about 0 to 80% cobalt (used as a nickel substitute), about
0.05 to 0.5% carbon, about 0.25-5% welding agent selected from the
group consisting of niobium and tantalum with a balance of iron. In
addition, the alloy may contain about 0-3% manganese, about 0-3%
titanium and about 0-1% aluminum. Preferably Mg or Ce is used
during melting to tie up sulfur which tends to promote crack
formation. Most preferably, Mg is used in an amount greater than
the amount of sulfur. Impurities are preferably limited to less
than about 0.1% sulfur, less than about 0.1% phosphorous and less
than about 1% silicon.
Most preferably, the welding material includes about 25-55% nickel,
about 0-30% cobalt, about 0.05-0.35% carbon, about 0.5-3% niobium
plus tantalum and a balance iron with incidental impurities.
Furthermore, filler metal is preferably limited to about 0-1.5%
manganese, about 0-2% titanium and about 0-0.5% aluminum. In
addition, about 0-0.5% cerium, magnesium or zirconium is preferably
used for tying up sulfur. Furthermore, it may be most advantageous
to limit cerium, magnesium or zirconium to less than 0.1%. In
addition, impurities are preferably limited to about 0.05% sulfur,
about 0.05% phosphorous and about 0.5% silicon.
DESCRIPTION OF PREFERRED EMBODIMENT
Several experimental heats were tested to find a combination of
ingredients that may be added to low CTE alloys without cracking
during multiple pass GMAW.
Composition of typical experimental heats tested are listed below
in Table 1 as heats numbers 1-14 (all compositions of this
specification are given in weight percent, unless specifically
expressed otherwise). Heat number 15 was a sample of Invar 36. Heat
number 16 was added to verify a filler metal essentially free of
calcium, copper, magnesium and manganese would operate
effectively.
TABLE 1
__________________________________________________________________________
Heat No. C Mn S Si Cu Ni Ti Nb Mg Ca P
__________________________________________________________________________
1 .068 .71 .005 .010 .48 35.47 .009 .007 .002 .000 .003 2 .105 .71
.006 .015 .50 35.55 .000 1.12 .003 .000 .004 3 .120 .72 .004 .053
.49 35.37 .000 1.13 .000 .012 .004 4 .107 .71 .005 .076 .50 35.59
.78 .054 .000 .017 .003 5 .21 .72 .005 .066 .49 34.89 1.10 .003
.000 .012 .003 6 .21 .71 .009 .058 .49 35.07 .037 .002 .000 .017
.003 7 .198 .72 .009 .015 .50 34.97 .000 .001 .003 .000 .003 8 .22
.72 .007 .017 .50 35.22 .000 1.87 .004 .000 .004 9 .129 .73 .007
.065 .024 35.75 .000 1.15 .000 .017 .004 10 .126 .72 .006 .066 .96
35.47 .000 1.13 .000 .017 .004 11 .128 .70 .005 .065 1.85 35.09
.000 1.14 .000 .016 .004 12 .136 .73 .007 .080 3.81 34.34 .000 1.14
.000 .022 .004 13 .163 .86 .008 0 0.022 40.48 .171 1.76 .004 .000
.005 14 .208 .73 .008 .037 0.036 35.24 .143 1.62 .007 .000 .005 15
.013 .33 .007 .000 .000 36.36 .027 .006 .004 .000 .003 16 .189 .00
.004 .025 .007 35.91 .36 2.00 .000 .001 .001
__________________________________________________________________________
The heats of Table 1 were tested for solidification range (values
in Table 1 have been rounded to the nearest one thousandth of a
weight percent to reflect accuracy of instrumentation used).
Test results are given below in Table 2.
TABLE 2 ______________________________________ HEAT LIQUIDOUS
.degree.C. SOLIDUS .degree.C. DIFFERENCE .degree.C.
______________________________________ 1 1471 1452 19 2 1466 1425
41 3 1467 1426 41 4 1467 1428 39 5 1462 1423 39 6 1468 1450 18 7
1470 1451 19 8 1462 1418 44 9 1469 1429 40 10 1465 1425 40 11 1462
1425 37 12 1451 1407 44 13 1468 1381 87
______________________________________
The difference between liquidous and solidous temperatures of the
test heats (18.degree.-44.degree. C.) was much improved over Invar
36 (heat 15) which may have a temperature differential of at least
80.degree. C. as measured between liquidous and incipient solidous.
This decreased solidification range contributes to reducing
cracking during solidification.
Heat numbers 1-12 were gas tungsten arc spot welded at 420 amp and
22 volts for 10 seconds in a single spot weld without changing
position. This 420 amp, 22 volt operation greatly exceeded minimum
required energy to weld. The excess energy applied additional
stress to the weld for evaluation under severe welding conditions.
As a result of this 10 second test, only heat numbers 9 and 12
cracked. Heat number 9 had a total crack length of 0.60 cm and heat
number 12 had a total crack length of 0.60 cm.
A more severe 20 second gas tungsten arc spot weld at 420 amp and
22 volts was then used to determine which filler metal compositions
had the best cracking resistance. Results of total crack length for
two separate tests are given below in Table 3.
TABLE 3 ______________________________________ TEST A TEST B TOTAL
CRACK TOTAL CRACK HEAT LENGTH (cm) LENGTH (cm) TOTAL (cm)
______________________________________ 1 6.2 5.5 11.7 2 0 0 0 3 3.0
2.4 5.4 4 6.0 7.9 13.9 5 1.5 0.5 2.0 6 6.9 1.5 8.4 7 0 0 0 8 0 0 0
9 6.2 6.4 12.6 10 2.4 2.8 5.2 11 6.3 7.8 14.1 12 5.4 4.1 9.5 16 0 0
0 ______________________________________
Heat numbers 2, 7, 8 and 16 produced the best results having no
cracks. The combination of carbon and niobium of heats 2, 8 and 16
was found to have the most preferred cracking resistance
properties. For purposes of this specification, it is recognized
that niobium and tantalum are interchangeable and that niobium or
tantalum may be used independently or in combination for welding
materials of the invention.
A cruciform or X-joint welding test at 420 amp and 22 volts was
then used to test filler metals under more rigorous welding
conditions. All tests were 9.5 cm in length. Test results are given
below in Table 4.
TABLE 4 ______________________________________ TEST A TEST B TOTAL
TOTAL TEST C CRACK CRACK TOTAL CRACK LENGTH LENGTH LENGTH TOTAL
HEAT (cm) (cm) (cm) (cm) ______________________________________ 1
1.1 1.4 4.4 6.9 2 0.4 0 0 0.4 3 0.4 0.6 0.7 1.7 4 0.4 1.1 1.4 2.9 5
0.4 0 0 0.4 6 2.0 1.8 5 8.8 7 7.5 3.8 3.9 15.2 8 0.1 0 0 0.1 9 0
1.3 0.4 1.7 10 0.8 0.8 0.6 2.2 11 1.0 0.8 0.6 2.2 12 0.6 0.8 1.1
2.5 16 0 0 0 0 ______________________________________
Again heat numbers 8 and 16 gave the best results with heat numbers
2 and 5 being the next best.
Welds produced at 415 amps and 22 V were tested for physical
properties. A bend test was used to measure propensity to crack
during bending or ductility. Impact tests were used to determine
strength in as welded condition and strength after a 1.5 hour heat
treatment in an inert 790.degree. C. atmosphere. Test results are
given below in Table 5.
TABLE 5 ______________________________________ BEND IMPACT TOTAL
IMPACT STRENGTH HEAT CRACK STRENGTH TREATED AT LENGTH AS WELDED
750.degree. C. FOR 1.5 HEAT (cm) (JOULES) HOURS (JOULES)
______________________________________ 1 X, 0.3 98 149 81 -- 2 0,
0.08 56 54 68 76 3 0, 0.08 87 94 81 82 77 83 4 0, 0 60 50 66 55 49
61 5 0, 0 27 26 30 26 24 23 6 0.5, 1.8 58 79 45 60 37 58 7 X, 0.08
68 77 89 41 76 89 8 0, 0 34 41 37 33 38 35 9 0, 0 71 74 72 66 74 10
0, 0 70 74 72 81 77 73 11 0, 0 61 65 68 68 62 12 0, 0 62 64 72 69
64 16 0, 0 24 27 29 -- ______________________________________ X
designates welded failure
The test data indicate that heat numbers 2, 8 and 16 rich in carbon
and niobium had physical properties acceptable for an Invar 36
weld. Niobium has been found to increase cracking resistance and
decrease impact strength. The upper limit of niobium in the filler
metal is essentially limited by the amount of acceptable reduction
in impact strength. Heat number 5, which relied upon carbon and
titanium had about one half of the impact strength of welds
produced using carbon and relatively low amounts of niobium (about
1.1%). Furthermore, during intermediate anneals, which are often
used in drawing weld wire to final size, titanium has a much
greater tendency to oxidize than niobium. Titanium tends to form
surface oxides during annealing which increase die wear. Predicted
CTE of the filler metals tested were calculated to be very close to
the base metal. It is preferred to add more magnesium or cerium
than sulfur to ensure tying up of sulfur and prevent sulfur rich
films. An addition of up to 0.5% Mg, Zr or Ce is preferred to limit
negative effects of sulfur inclusions.
Heat numbers 13 and 14 were tested for coefficient of thermal
expansion (CTE) in accordance with ASTM E228. To match CTE,
preferably the ratio of nickel, iron and cobalt approximates the
ratio of nickel, iron and cobalt in the base metal to be welded.
Advantageously, weight percent of nickel, iron and cobalt is within
10 percent of the base metal weight percent. For example, a welding
material for an alloy having 36 weight percent nickel would have a
weight percentage nickel of about 32.4 to 39.6. Most
advantageously, nickel, cobalt and iron are each within about 2
weight percent of the base metal. Heat 13 compared favorably to
Invar 42. In addition, when welding iron-nickel low coefficient of
thermal expansion alloy systems that do not contain cobalt, it is
most advantageous not to substitute cobalt for nickel in the
welding material. Invar 42 has a maximum CTE of 4.7
cm/cm/.degree.C. .times.10.sup.-6 at 300.degree. C. and a maximum
CTE of 7.4 cm/cm/.degree.C. .times. 10.sup.-6 at 450.degree. C.
Heat number 13 measured 5.07 cm/cm/.degree.C..times.10.sup.-6 at
300.degree. C. and 8.33 cm/cm/.degree.C..times.10.sup.-6 at
450.degree. C. The proximity of these values to specified values
for Invar 42 specification would result in minimal stress from
thermal cycling.
Heat number 14 (Invar 36 filler metal), also was found to have a
close CTE to maximum Invar 36 specifications. Table 6 below
compares heat number 14 to base metal maximum values and to CTE
data extrapolated from FIG. 2 of Witherell's U.S. Pat. No.
3,184,577 ('577).
TABLE 6 ______________________________________ COEFFICIENT OF
THERMAL EXPANSION (cm/cm/.degree.C. .times. 10.sup.-6) TEM-
WITHERELL PERATURE INVAR 36 U.S. Pat. No. .degree.C. (MAX.) HEAT
NO. 14 3,184,577 ______________________________________ 93 2.0 2.3
2.8 149 2.5 2.8 5.4 260 4.9 5.9 12.2 371 7.9 8.9 16.7
______________________________________
As shown in Table 6, CTE for heat number 14 compares favorably to
base metal Invar 36 and is significantly improved over the '577
patent.
Welding material of the invention is advantageously within the
following ranges expressed in Table 7.
TABLE 7 ______________________________________ BROAD NARROW
______________________________________ Nickel 10-80 25-55 Cobalt
0-80 0-30 Carbon 0.05-0.5 0.05-0.35 Niobium 0.25-5 0.5-3 and/or
Tantalum Manganese 0-3 0-1.5 Titanium 0-3 0-2 Aluminum 0-1 0-0.5
Copper 0-5 0-2 Magnesium 0-0.5 0-0.1 Cerium 0-0.5 0-0.1 Zirconium
0-0.5 0-0.1 Sulfur 0-0.1 0-0.05 Silicon 0-1 0-0.5 Phosphourous
0-0.1 0-0.05 Iron Balance Balance
______________________________________
Nickel, iron and cobalt ranges are advantageously adjusted to
amounts approximate to nickel iron and cobalt amounts contained in
low coefficient of thermal expansion base metals to be welded. Most
advantageously, nickel, iron and cobalt are further adjusted to
achieve a matched CTE. The most advantageous range for Invar-type
filler metals is 30 to 50% nickel, 0.05 to 0.35% carbon, 0.5 to 3%
niobium, 0 to 1.5% manganese, 0 to 2% titanium, 0 to 0.1% magnesium
with an iron balance.
A welding material of the invention was tested for submerged arc
welding. Filler metal of heat numbers 13 and 14 was combined with
Incoflux.RTM. 6 submerged arc flux (Incoflux is a registered
trademark of the Inco family of companies). Incoflux 6 submerged
arc flux has the following compositions:
______________________________________ Weight Ingredient Percent
______________________________________ Al.sub.2 O.sub.3 15-40
CaF.sub.2 40-70 MgO 3-7 Ni 1-5 K.sub.2 SiO.sub.3 1-5 Na.sub.3
AlF.sub.6 3-7 TiO.sub.2 3-7
______________________________________
Bare filler metals of this invention, for Invar 36 and 42, have
operated unexpectedly well. For example, a 0.11 cm diameter Invar
36 filler metal successfully operated at 325-350 amps, at 32 volts
and 15.9 m/s. Typically, operating parameters for filler metals
used in submerged arc welding of nickel-base alloys are limited to
240-250 amps and slower feed rates. The great resistance to
cracking and porosity of the filler metal allows welding operations
at increased rates.
Welding material of the invention have also been successfully used
as a core wire for a coated electrode. Advantageously, flux of the
invention contains metal carbonate selected from the group
consisting of calcium carbonate, barium carbonate, manganese
carbonate and strontium carbonate for control of flux
solidification. It has been found to be advantageous to add coarse
calcium carbonate (74 to 420 microns) to the flux for preferred
drying properties. Cryolite, Tri-Manox.RTM. brand brown manganese
oxide (Mn.sub.3 O.sub.4 80%, SiO.sub.2 5%, Fe 10%) and/or alkaline
metal fluoride selected from the group consisting of CaF.sub.2,
BaF.sub.2 and SrF.sub.2 may be used for increasing fluidity.
Advantageously, magnetite is used to let silicon pick up in the
weld deposit. Rutile and/or zirconia may be used as filler. In
addition, rutile and other titanium-containing compounds such as
NiTi and FeTi may be used to limit porosity formed from nitrogen.
Natrosol.RTM. brand hydroxyethycellulose (HEC) is advantageously
added as an extrusion aid and to provide green strength. Bentonite
is advantageously added to provide strength after baking. Flux
coated weld rods of the invention contained a total of 30 weight
percent flux and binder after baking. And finally, any binder such
as water glass may be used to hold the flux to the weld rod. Binder
specifically used was a liquid having manufacturer's specification
of 31.3-32.5% SiO.sub.2, 10.5-11.5% Na.sub.2 O and 2.83-2.98%
SiO.sub.2 +Na.sub.2 O, having a viscosity at 20.degree. C. of
780-1140 centipoise and a specific gravity at 20.degree. C. of
about 1.59-1.67 g/cm.sup.3.
Advantageously, niobium and carbon compounds are added to maintain
sufficient niobium and carbon content in the weld deposit. Most
advantageously, a combination of NiNb, FeNb, (Ni, C) and (Fe, C) is
added in a proportion that maintains niobium levels and carbon
levels. In addition, NiTi and/or FeTi may be added to the flux to
control porosity and to a lesser extent contribute nickel and iron
to the weld deposit. Advantageously, nickel and iron components are
controlled to match base metal weight percents. Desired ranges of
the ingredients and compositions of two specific coated electrodes
which successfully operated are provided below in Table 8.
TABLE 8
__________________________________________________________________________
Broad Intermediate Specific Compositions
__________________________________________________________________________
Alkaline Metal Carbonate 10-40 20-35 15 (CaCO.sub.3) 15
(CaCO.sub.3) + 5 (SrCO.sub.3) Crolite 0-45* 0-35** 25 25 Alkaline
Metal Fluoride 0-40* 0-30** Rutile 0-45 20-45 30 30 Zirconia 0-20
Magnetite 0-10 6 6 Mn.sub.3 O.sub.4 (80%), 5% SiO.sub.2, 0-15 5 10%
Fe FeNb 0-15 3 (65Nb, 34Fe, 1Al) 3 (65Nb, 34Fe, 1Al) Fe, C 0-15
NiNb 0-15 Ni, C 0-15 1.5 (75 Ni, 25C) 1.5 (75Ni, 25C) FeTi 0-15
NiTi 0-15 Bentonite 0-5 2-5 4 4 Hydroxyethylcellulose 0-4 0-2 0.5
0.5 Binder 0-4 20 (sodium silicate) 20 (sodium silicate) Water
Cellulose or HEC 1.25 1.25
__________________________________________________________________________
*Cryolite plus Alkaline Metal Fluoride equals 5-45% **Cryolite plus
Alkaline Metal Fluoride equals 10-35%
It is recognized that the welding material of the invention may be
welded in various welding configurations including bare filter
metal GTAW, GMAW, SAW, coated electrode, flux-cored and other known
configurations provided weld deposit composition is maintained.
Weld deposit parameters are given below in Table 9.
TABLE 9 ______________________________________ BROAD INTERMEDIATE
NARROW ______________________________________ C 0.05-0.35 0.05-0.30
0.1-0.25 Mn 0-2.5 0-1.5 0-0.8 Fe Bal. Bal. Bal. S 0-0.05 0-0.02
0-0.01 Si 0-1 0-1 0-.75 Cr 0-2 0-1 0-0.5 Al 0-0.5 0-0.25 0-0.2 Ti*
0-0.75 0-0.5 0-0.4 Nb 0.1-4 0.5-3 1-2.5 P 0-0.05 0-0.02 0-0.01 Mg
0-0.1 0-0.1 0.0005-0.075 Cu 0-4 0-2 0-0.5 Ag, B, Sn, Zn 0-0.01
0-0.005 0-0.001 Ni + Co .+-.10* .+-.5* .+-.2* Ni (Invar 36) 31-40
33-38 34.25-36.75 Ni (Invar 42) 36-45 39-42 39.5-41.5
______________________________________ *Weight percent of nickel
plus cobalt in relation to weight percent of nickel plus cobalt in
low coefficient of thermal expansion base metal of nominal
composition containing nickel and iron.
In conclusion, welding materials of the invention have been
successfully produced that have a matched CTE, strength and
ductility. Furthermore, alloys of the carbon and niobium
combination has allowed welding of thick sections. GMAW of low CTE
alloys and multiple pass welding without cracking. The present
invention contemplates any range definable by any two specific
ranges disclosed in the specification and any range definable
between any specified values in the specification. For example, the
invention contemplates weld deposits having 0.05 to 0.30 carbon and
filler metal having 0.06-0.37 carbon.
While in accordance with the provisions of the statute, there is
illustrated and described herein specific embodiments of the
invention. Those skilled in the art will understand that changes
may be made in the form of the invention covered by the claims and
the certain features of the invention may sometimes be used to
advantage without a corresponding use of the other features.
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